The biophysically relevant exposure values to optical radiation can be determined
with the formulae below. The formulae to be used depend on the range of radiation
emitted by the source and the results should be compared with the corresponding exposure
limit values indicated in Table 1.1. More than one exposure value and corresponding
exposure limit can be relevant for a given source of optical radiation.

Numbering (a) to (o) refers to corresponding rows of Table 1.1.

For the purposes of these Regulations, the formulae above can be replaced by the following
expressions and the use of discrete values as set out in the following tables:

Table 1.1: Exposure limit values for non-coherent optical radiation

Note 1: The range of 300 to 700 nm covers parts of UVB, all UVA and most of visible
radiation; however, the associated hazard is commonly referred to as
blue light hazard. Blue light strictly speaking covers only the range of approximately 400 to
490 nm.

Note 2: For steady fixation of very small sources with an angular subtense < 11 mrad,
L B can be converted to E B . This normally applies only for ophthalmic instruments
or a stabilised eye during anaesthesia. The maximum
“stare time” is found by:t max = 100 / E B with E B expressed in W m -2 . Due to eye movements
during normal visual tasks this does not exceed 100 s.

Table 1.2: S () [dimensionless], 180 nm to 400 nm

λ in nm

S (λ)

λ in nm

S (λ)

λ in nm

S (λ)

λ in nm

S (λ)

λ in nm

S (λ)

180

0.0120

228

0.1737

276

0.9434

324

0.000520

372

0.000086

181

0.0126

229

0.1819

277

0.9272

325

0.000500

373

0.000083

182

0.0132

230

0.1900

278

0.9112

326

0.000479

374

0.000080

183

0.0138

231

0.1995

279

0.8954

327

0.000459

375

0.000077

184

0.0144

232

0.2089

280

0.8800

328

0.000440

376

0.000074

185

0.0151

233

0.2188

281

0.8568

329

0.000425

377

0.000072

186

0.0158

234

0.2292

282

0.8342

330

0.000410

378

0.000069

187

0.0166

235

0.2400

283

0.8122

331

0.000396

379

0.000066

188

0.0173

236

0.2510

284

0.7908

332

0.000383

380

0.000064

189

0.0181

237

0.2624

285

0.7700

333

0.000370

381

0.000062

190

0.0190

238

0.2744

286

0.7420

334

0.000355

382

0.000059

191

0.0199

239

0.2869

287

0.7151

335

0.000340

383

0.000057

192

0.0208

240

0.3000

288

0.6891

336

0.000327

384

0.000055

193

0.0218

241

0.3111

289

0.6641

337

0.000315

385

0.000053

194

0.0228

242

0.3227

290

0.6400

338

0.000303

386

0.000051

195

0.0239

243

0.3347

291

0.6186

339

0.000291

387

0.000049

196

0.0250

244

0.3471

292

0.5980

340

0.000280

388

0.000047

197

0.0262

245

0.3600

293

0.5780

341

0.000271

389

0.000046

198

0.0274

246

0.3730

294

0.5587

342

0.000263

390

0.000044

199

0.0287

247

0.3865

295

0.5400

343

0.000255

391

0.000042

200

0.0300

248

0.4005

296

0.4984

344

0.000248

392

0.000041

201

0.0334

249

0.4150

297

0.4600

345

0.000240

393

0.000039

202

0.0371

250

0.4300

298

0.3989

346

0.000231

394

0.000037

203

0.0412

251

0.4465

299

0.3459

347

0.000223

395

0.000036

204

0.0459

252

0.4637

300

0.3000

348

0.000215

396

0.000035

205

0.0510

253

0.4815

301

0.2210

349

0.000207

397

0.000033

206

0.0551

254

0.5000

302

0.1629

350

0.000200

398

0.000032

207

0.0595

255

0.5200

303

0.1200

351

0.000191

399

0.000031

208

0.0643

256

0.5437

304

0.0849

352

0.000183

400

0.000030

209

0.0694

257

0.5685

305

0.0600

353

0.000175

210

0.0750

258

0.5945

306

0.0454

354

0.000167

211

0.0786

259

0.6216

307

0.0344

355

0.000160

212

0.0824

260

0.6500

308

0.0260

356

0.000153

213

0.0864

261

0.6792

309

0.0197

357

0.000147

214

0.0906

262

0.7098

310

0.0150

358

0.000141

215

0.0950

263

0.7417

311

0.0111

359

0.000136

216

0.0995

264

0.7751

312

0.0081

360

0.000130

217

0.1043

265

0.8100

313

0.0060

361

0.000126

218

0.1093

266

0.8449

314

0.0042

362

0.000122

219

0.1145

267

0.8812

315

0.0030

363

0.000118

220

0.1200

268

0.9192

316

0.0024

364

0.000114

221

0.1257

269

0.9587

317

0.0020

365

0.000110

222

0.1316

270

1.0000

318

0.0016

366

0.000106

223

0.1378

271

0.9919

319

0.0012

367

0.000103

224

0.1444

272

0.9838

320

0.0010

368

0.000099

225

0.1500

273

0.9758

321

0.000819

369

0.000096

226

0.1583

274

0.9679

322

0.000670

370

0.000093

227

0.1658

275

0.9600

323

0.000540

371

0.000090

Table 1.3: B (), R () [dimensionless], 380 nm to 1400 nm

λ in nm

B (λ)

R (λ)

300 ≤λ < 380

0.01

—

380

0.01

0.1

385

0.013

0.13

390

0.025

0.25

395

0.05

0.5

400

0.1

1

405

0.2

2

410

0.4

4

415

0.8

8

420

0.9

9

425

0.95

9.5

430

0.98

9.8

435

1

10

440

1

10

445

0.97

9.7

450

0.94

9.4

455

0.9

9

460

0.8

8

465

0.7

7

470

0.62

6.2

475

0.55

5.5

480

0.45

4.5

485

0.32

3.2

490

0.22

2.2

495

0.16

1.6

500

0.1

1

500 < λ≤ 600

100.02·(450-λ)

1

600 < λ≤ 700

0.001

1

700 < λ≤ 1050

—

100.002·(700-λ)

1050 < λ≤ 1150

—

0.2

1150 < λ≤ 1200

—

0.2100.02·(1150-λ)

1200 < λ≤ 1400

—

0.02]

F84[Part 2

Laser Optical Radiation

The biophysically relevant exposure values to optical radiation can be determined
with the formulae below. The formulae to be used depend on the wavelength and duration
of radiation emitted by the source and the results should be compared with the corresponding
exposure limit values indicated in the Tables 2.2 to 2.4. More than one exposure value
and corresponding exposure limit can be relevant for a given source of laser optical
radiation.

Coefficients used as calculation tools within the Tables 2.2 to 2.4 are listed in
Table 2.5 and corrections for repetitive exposure are listed in Table 2.6.

Notes:

dP

power expressed in watt [W];

dA

surface expressed in square metres [m2];

E (t), E

irradiance or power density: the radiant power incident per unit area upon a surface, generally expressed in
watts per square metre [W m
-2]. Values of E(t), E come from measurements or may be provided by the manufacturer of the equipment;

H

radiant exposure: the time integral of the irradiance, expressed in joules per square metre [Jm-2];

limiting aperture: the circular area over which irradiance and radiant exposure are averaged;

G

integrated radiance: the integral of the radiance over a given exposure time expressed as radiant energy
per unit area
of a radiating surface per unit solid angle of emission, in joules per square metre
per steradian [Jm
-2 sr -1].

c Due to lack of data at these pulse lengths, ICNIRP recommends the use of the 1 ns
irradiance limits.

d The table states values for single laser pulses. In case of multiple laser pulses,
then the laser pulse durations of pulses falling within an interval Tmin (listed in
table 2.6) must be added up and the resulting time value must be filled in for t in
the formula: 5.6 10 3 t 0.25

a If the wavelength or another condition of the laser is covered by two limits, then
the more restrictive applies.

b For small sources subtending an angle of 1.5 mrad or less, the visible dual limits
E from 400 nm to 600 nm reduce to the thermal limits for 10 s
≤ t<T1 and to photochemical limits for longer times. For T1 and T2 see Table 2.5. The photochemical retinal hazard limit may also be expressed as a
time integrated radiance G = 10
6 CB [J m-2 sr-1] for t > 10s up to t = 10000 s and L=100 CB [W m-2 sr-1] for t> 10000 s. For the measurement of G and Lγm must be used as averaging field of view. The official border between visible and
infrared is 780 nm as defined by the CIE. The column with wavelength band names is
only meant to provide better overview for the user. (The notation G is used by CEN;
the notation L t is used by CIE; the notation L
P is used by IEC and CENELEC.)

d For measurement of the exposure value the consideration of γ is defined as follows: If α (angular subtense of a source) > γ (limiting cone angle, indicated in brackets in the corresponding column) then the
measurement field of view
γm should be the given value of γ. (If a larger measurement field of view is used, then the hazard would be overestimated).
If
α < γ then the measurement field of view γm must be large enough to fully enclose the source but is otherwise not limited and
may be larger than
γ.

Table 2.4: Exposure limit values for laser exposure of skin

a If the wavelength or another condition of the laser is covered by two limits, then
the more restrictive applies

Each of the following three general rules should be applied to all repetitive exposures
as occur from repetitively pulsed or scanning laser systems:

1. The exposure from any single pulse in a train of pulses shall not exceed the exposure
limit value for a single pulse of that pulse duration.

2. The exposure from any group of pulses (or sub-group of pulses in a train) delivered
in time t shall not exceed the exposure limit value for time t.

3. The exposure from any single pulse within a group of pulses shall not exceed the
singlepulse exposure limit value multiplied by a cumulative-thermal correction factor
Cp=N-0.25, where N is the number of pulses. This rule applies only to exposure limits
to protect against thermal injury, where all pulses delivered in less than Tmin are
treated as a single pulse.

]

F85[Part 3

Assessment, Measurement and Calculation of Exposure

The methodology applied in assessment, measurement and/or calculations shall follow
the standards of the International Electrotechnical Commission (IEC) in respect of
laser radiation and the recommendations of the International Commission on Illumination
(CIE) and the European Committee for Standardisation (CEN) in respect of non-coherent
radiation.

In exposure situations which are not covered by these standards and recommendations,
and until appropriate EU standards or recommendations become available, assessment,
measurements and/or calculations shall be carried out using available international
science-based guidelines. In both exposure situations, the assessment may take account
of data provided by the manufacturers of the equipment when it is covered by relevant
Community Directives.
]